邻近既有线土石方控制爆破技术应用

利用顸留隔墙的施工工艺,先对隔墙与最终边坡间的大量土石方进行拉槽松动控制爆破,再对预留隔墙土石方进行弱松动或龟裂爆破,采解决邻近既有线的土石方爆破开挖问题.对邻近既有线的土石方爆破,采用松动控制爆破,通过堆码沙袋墙来防止边坡爆破滚石、根据离既有线距离的远近给炮孔覆盖沙袋、给爆区覆盖废胶皮及安全网等安全防护措施,避免了个别爆破飞石和滚石影响既有线,保证了既有线的行车安全.     

中心支撑-钢框架结构抗震性能和设计方法综述

为推动非双重体系中心支撑-钢框架结构的应用,总结了国内外关于中心支撑-钢框架结构抗震性能的研究成果,对比了国际主流规范在抗震设计方法上的差异.指出中国现行规范存在的不足,认为中心支撑-钢框架结构的抗震设计未充分考虑支撑及其连接的低周疲劳寿命,对高延性和低延性的结构不应采用相同的抗震设计方法,低延性中心支撑-钢框架结构在...     

Characterization of motion power loss of off-road wheeled robot in a slippery terrain

For the first time in realm of power study of off-road wheeled robots, this study deals with motion power loss due to slippage of robot wheels traversed on slippery terrain. For this purpose, effects of slippery terrain type (solid balls with diameter of 0.0127, 0.0254, and 0.0508 m), tire air pressure (20.68, 34.47, and 55.16 kPa), and robot forward speed (0.17, 0.33, and 0.5 m/s) on the power loss were characterized. Derived results proved that the increasing effect of slippery terrain type on the power loss was dominant (1.08 and 3.21 times) than that of robot forward speed and tire air pressure, respectively. Meanwhile, the increasing effect of robot forward speed on the power loss was prevailed (2.98 times) than that of tire air pressure. Hence, to minimize the power loss of the robot traversed on each type of slippery terrain, adjustment of robot forward speed should be considered as first priority. A comparison between motion power loss (43.60–249.40 W) and provided motion power for the robot (136–436.37 W) implies that 12.93–75.44% of provided motion power was wasted by slippage of the robot wheels on slippery terrains. Overall, the analytical results obtained in this study lead to open a new prospection for comprehending of the power loss trends of off-road wheeled robots traversed on slippery terrains. As slippery terrain composed of solid balls, the results can be especially utilized for final phase of unloading robotic operations of catalyst handling procedure in process towers and reactors of oil, gas, petrochemical, and chemical industries.     

女胸衣肩带滑落的原因及改进

针对胸衣肩带滑落现象 ,以标准人体为研究对象 ,查找肩带滑落原因 ,从结构、款式、面料及肩带与肩形搭配方面提出应对方法。以结构改进为研究重点 ,综合运用物理的力学分析和数学的解析几何分析方法 ,导出背部肩带的设计角θ:平行式肩带为 78.48° ,交叉式肩带为 76.38°。     

备自投装置在武汉电网中的应用分析

通过备自投装置在武汉电网中的应用情况分析,以武汉电网具有典型意义的沌口变电站为研究对象,对该站备自投接入方案及动作逻辑进行了探讨,指出作为电力系统中一种重要的自动装置,备自投对提高供电可靠性有着不可替代的作用。     

工程量清单计价工程结算审核中几个问题的探讨

文章从工程量清单计价工程结算审核问题入手,探讨工程量清单计价工程结算审核中应注意的几个问题。     

利用浅地层蓄能的空调系统在过渡性地区应用探讨

本文针对过渡性地带目前采用被动式降温措施，提出利用浅地层蓄能的空调系统，并对该系统运行进行实测及舒适性评价，展望该空调系统应用前景，指出该空调系统的应用将促进建筑科学的发展．     

短天窗点间隔下邻近既有隧道爆破方案的优化

为评估短天窗点间隔条件下爆破对邻近既有隧道衬砌结构安全性的影响,以福平铁路苔井山隧道为依托,采用数值模拟对两种不同爆破方案1.4m进尺下的邻近隧道各监测点的爆破振速进行了分析。结果表明:全断面爆破方案最大振速为6.04cm/s,超过现场施工最大振速允许值3cm/s,而优化后的分天窗爆破方案最大振速仅为2.75cm/s,且能充分利用天窗点,加快施工进度,安全经济高效,同时也可为以后类似工程提供借鉴。     

纬编双轴向多层衬纱织物的圆柱成型研究

分析纬编双轴向多层衬纱织物的结构和性能特点,进行了该织物的圆柱成型实验,并在实验的基础上描述圆柱成型的特点及规律,研究圆柱成型过程中的纱线滑移现象.研究确认:织物45°方向上衬经衬纬纱交叉点处的夹角随成型高度的增加而减小,呈非线性变化趋势;织物达到成型极限时,圆柱的高度/直径比与直径呈线性关系,直径小的圆柱其织物成型的相对极限高度要高一些;织物的剪切变形极限角约为25°.     

Dynamic Analysis and Control Synthesis of Undesired Slippage of End-Effectors in a Cooperative Grasping

This paper addresses dynamic analysis and control synthesis of object grasping in a cooperative multirobot system with n-serial manipulators from an undesired slippage point of view. Two control approaches are presented in this article; a modified version of a conventional method in grasp synthesis and a new method based on a new modeling of system dynamics. A new formulation for frictional contact is used in dynamical modeling, where equality and inequality equations of the standard Coulomb friction model are all converted to a single second-order differential equation. A multiphase controller is utilized to control the object trajectory tracking as well as object slippage in the new control approach. Performance and robustness of both approaches are studied numerically. The results show superiority of the new method and its desirable and excellent performance.